This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The GAL genes make up one of the best characterized eukaryotic systems of transcriptional regulation, the galactose/melibioseregulon of the yeast, Saccharomyces cerevisiea. Saccharomyces cerevisiea converts galactose from the surrounding medium toglucose-1-phosphate using the GAL enzymes, two of them being Gal4 and Gal80. Gal80 acts as a transcription repressor when bound to Gal4. Our goal is to determine the structure of the Gal4 and Gal80 binding sites, pre- and post-binding, via NMR analytical techniques.